[en] The problem of wave propagation in a magnetized plasma slab was studied by particle simulation of plasma. In the model, a warm homogeneous plasma slab is bounded by vacuum on two sides. Using a 2-D electrostatic particle code, the author simulated two different cases. For the sharp boundary case with wave propagation perpendicular to the external field, two branches of surface waves are found to exist. A theoretical analysis showed that the discreteness of the modes is due to the quantization condition imposed by the boundary. A generalized surface mode damped in time appears below the second cyclotron harmonic and it is found that by specifying the complex frequency in the Bernstein wave dispersion relation, the wavelength and attenuation in the direction normal to the slab is predicted accurately. Short time-scale phase mixing, damping, and recurrence phenomena of Bernstein body modes are also observed. Oblique propagation of the waves are studied by the magnetic field perpendicular to the plasma-vacuum interface. For the free-boundary model, the confinement is provided by fixed ion plus the magnetic field. Wave propagation was studied with and without an external magnetic field applied parallel to the slab boundaries

[en] Part One examines the properties of electron cyclotron harmonic waves by means of computer simulation. The electromagnetic cyclotron harmonic modes not previously observed in simulation are emphasized and compared with the better known electrostatic (Bernstein) modes for perpendicular propagation. The investigation is performed by a spectrum analysis (both wavelength and frequency) of the thermal equilibrium electromagnetic fluctuation fields present in the simulation. A numerical solution of the fully electromagnetic dispersion relation shows that extreme frequency resolution is necessary to discern shifts of the electromagnetic mode frequencies from the cyclotron harmonics except at high plasma density or temperature. The simulation results show that at high plasma pressure the amplitude of the electromagnetic modes can become greater than that of the electrostatic modes. Part Two examines the interaction of an external electromagnetic wave with the electrostatic cylotron harmonic modes. The stimulated Raman scattering with an extraordinary wave as the pump is observed to occur in a wavelength regime where it would be prevented by Landau damping in an unmagnetized plasma

[en] Certain fast wave scattering parameters from a sixth order mode conversion equation, which represents the coupling of five propagating wave branches in an inhomogeneously magnetized plasma, are shown to be independent of absorption. However, the mode conversion coefficient C₂₃ between the X-mode and the O-mode where both propagate in the same direction is not one of these. A recently developed analytical method is applied to calculate C₂₃ and one of the nonzero reflection coefficients. Empirical formulas are found for these two coefficients. The result shows that C₂₃ is not exactly independent of absorption, but for many cases has an unusually weak dependence. This explains a previous numerical result showing that C₂₃ is independent of absorption to numerical accuracy. The coefficient C₃₂ is also calculated by the same method and is shown to be equal to C₂₃ as required by a proven reciprocity relation. The weak dependence of C₂₃ on absorption has to be taken into consideration by any theory that attempts to treat a five branch problem as two separated three branch problems

[en] The author starts with the dispersion relation for transverse-electric (T.E.) waves with wavevector perpendicular to the magnetic field in a two-component Maxwellian plasma described to all orders of the temperature. Standard Newton's method furnishes the k² roots of the dispersion relation. Numerical search is helped by knowledge of various analytical expressions for the position of the roots in limiting or asymptotic cases. When ω<ωsub(ci) three series of complex roots and an isolated one are found. The isolated root is the cold plasma solution. The position of the first roots of the three series is shown. The domain of the first ion cyclotron harmonics (i.c.h.) and ωsub(LH) are determined. (Auth.)

[en] The peculiarities of magnetostatic resonances on a tri-layered (ferromagnetic/non-magnetic spacer/ferromagnetic) stripe have been studied. It has been shown that the role of dynamic demagnetising effects at the edges of the stripe depends on the symmetry of the mode: while in anti-symmetric 'optical' modes the magnetisation practically vanishes at the edges, it remains definitely non-zero in the case of symmetric 'acoustical' modes. In a tri-layer with non-identical ferromagnetic mono-layers, the structure of an individual mode can become extremely complex and asymmetric. Typically, it contains two spatial harmonics, which means that every single mode will produce two optical responses in a Brillouin spectrometer, and the distribution of the dynamic magnetisation in layers differs significantly. To quantify the investigated effects the analytical technique, developed earlier for mono-layered stripes, has been extended to the multilayer case

[en] Motivated by the observation of anomalously intense radiation at frequencies sharply peaked about the electron cyclotron harmonics, the behavior of high frequency flute modes in a weakly inhomogeneous magnetoplasma is investigated. The longitudinal approximation is eschewed and the coupling of Bernstein modes with electromagnetic modes is analyzed. A graphical method is described for visualizing the salient features of mode behavior in this inhomogeneous plasma, and a highly resonant coupling instability is proposed as the energy generating mechanism for the radiation

[en] We study the classical and quantum properties of a degenerate optical parametric oscillator (DOPO) tuned to the first family of transverse modes at the down-converted frequency, under the injection of a resonant TEM₁₀ mode. Unlike the usual single-mode DOPO with injected signal, large levels of squeezing are predicted even for relatively large injections. We interpret these results in connection with the spontaneous symmetry breaking predicted for this system in the absence of injection and with the existence of a bifurcation giving rise to the switching on of the (noninjected) TEM₀₁ mode.

[en] A continuum limit is considered for a diatomic lattice system with a cubic nonlinearity. A long wave equation describing the interaction of acoustic and optical modes is obtained. It reduces, in certain approximations, to equations having coupled wave solutions. The solutions exhibit trapping of an optical mode by an acoustic soliton. The form of the trapped optical wave depends on the mass ratio of adjacent particles in the diatomic lattice. (author)

[en] Nonlinear dissipation of the parametrically driven electron Bernstein mode coupled with an ion-sound wave is considered. On the basis of a simple physical model, the anomalous collision frequency and anomalous absorption length are obtained. (orig.)

[en] The properties of Bernstein modes were investigated through computer simulations using two-dimensional and two-and-one-half-dimensional (i.e., two spatial and three velocity coordinates) electrostatic models with fixed magnetic field. The measured discrete spectrum was found to agree with the linear dispersion relation for these modes. The quasi-periodic phenomenon of early phase-mixing damping and later recurrence, predicted by Baldwin and Rowlands, was observed. For large wavenumber k/sub perpendicular/, the initial damping rate is the same as that for Landau damping in an unmagnetized plasma; for small k/sub perpendicular/, however, it is much stronger. The recurrence peaks slowly damp in time at a rate proportional to k²/sub perpendicular/D, where D is the measured cross-field particle diffusion coefficient which is dominated by convective transport. Finally, splitting of the main spectral peaks and the appearance of subpeaks at half-integral multiples of the cyclotron frequency are observed and may be explained by nonlinear mode coupling